Airway devices are widely used in hospital surgical environments to provide respiratory assistance and ventilate patents during medical procedures. While there are a multitude of airway devices currently on the market, one popular airway device is an endotracheal tube and another is a supra-glottic support device, such as a laryngeal tube. While the use of these devices is widespread, there are disadvantages associated with each of these devices.
Endotracheal tubes, for example, are used to ventilate patients requiring anesthesia and/or respiratory assistance. An example of a conventional endotracheal tube is a plastic tube, which is inserted into a subject's mouth, passed down the trachea through the vocal cords, and lodged in the trachea proximal (or above) the lungs. The endotracheal tube may have a cuff or balloon portion surrounding the circumference of the endotracheal tube near the distal end that rests in the subject's trachea. After the endotracheal tube has been inserted properly, the cuff may be inflated to seal against the wall of the trachea. Once sealed, positive pressure ventilation may be used to provide respiratory assistance and, if desired, anesthesia or other gas, gas mix, etc., to the patient though the endotracheal tube via a ventilator. The cuff provides a seal that tends to block liquids and solids from passing along the outside of the endotracheal tube between the tube and the trachea wall and entering the subject's lungs.
In its basic (standard) version, the supraglottic laryngeal tube is made up of a tube with a larger balloon cuff in the middle (oropharyngeal cuff) and a smaller balloon cuff at the end (esophageal cuff). The tube is kinked at an angle of 30-45° in the middle, with the kink being located in the larger cuff. There are a number of openings in the anterior wall of the tube that are used for ventilating a patient. In some configurations, for example, there are two apertures located between the two cuffs, through which ventilation takes place. Both cuffs are inflated through a single small lumen line and pilot balloon. The cuffs are high-volume, low-pressure cuffs with inflating volume ranging from 10 ml (size 0) to 90 ml (size 5).
In patients that require ventilation with an airway device (e.g., critically ill or injured subjects), it is important to maintain a continuous airway. In such patients, if ventilation begins with a supra-glottic support device (e.g., a laryngeal tube) and intubation subsequently becomes necessary, the supra-glottic support device must be removed from the patient so that an endotracheal tube can be placed. Doing so, however, requires that the patient's airway be temporarily disrupted while also increasing the risk that the patient's airway may not be recovered. Additionally, placing an endotracheal tube requires the skill of an experienced medical professional, who may not be present in all circumstances in which unexpected intubation is required.